1. Field of the Invention
The present invention relates generally to the field of semiconductor package device. More particularly, the present invention relates to a leadframe package suited for high-speed data rate applications.
2. Description of the Prior Art
As known in the art, semiconductor memories such as DRAMs or SDRAMs are arranged close to the core logic unit or execution unit and can be accessed much faster than the disk drive. Conventionally, DRAMs or SDRAMs are linked to the execution unit by a memory controller and stand-alone memory bus. To meet the bandwidth requirements in recent consumer electronics market, DDR3 SDRAM or double-data-rate three synchronous dynamic random access memory has been widely developed for high-speed digital interface applications, for example, high-performance graphics, where high bandwidth data transfer between frame buffers is required.
DDR3 SDRAM is a random access memory technology used for high speed storage of the working data of a computer or other digital electronic device. The primary benefit of DDR3 is the ability to transfer I/O data at eight times the speed of the memory cells it contains, thus enabling faster bus speeds and higher peak throughput than earlier memory technologies. However, there is no corresponding reduction in latency, which is therefore proportionally higher. Typically, DDR3 modules can transfer data at a rate of 800-2133 MT/s using both rising and falling edges of a 400-1066 MHz I/O clock. The MT/s is normally twice that of MHz by double sampling, one on the rising clock edge, and the other, on the falling.
To achieve high-speed data rate, the channel performance, including the package and the PCB, between the DRAM controller and the DRAM chip plays a significant role. Typically, to improve the channel performance and to preserve a better signal and power integrity, a DDR3 SDRAM memory controller is assembled using ball grid array (BGA) package and 4-layer PCB. However, the BGA package and the 4-layer PCB are costly. It would be desirable to use a less expensive packaging technique such as low-profile quad flat (LQFP) package without compromising the data transfer rate.